Starting mechanism for magnetos



S. C. McKEOWN.

STARTING MECHANISM FOR MAGNETOS.

APPLICATION FILED JULY 11., I911.

PatentedSept. 6

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S. C. McKEOWN.

STARTING MECHANISM FOR MAGNETOS.

APPLICATION FILED JULY 11, 19H.

Patented Sept. 6, 1921.

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APPLICATION HLED JULY I1. 1917.

Patented Sept. 6, 1921.

3 $HEETS-SHEET 3- 3140c mto'z UNITED STATES PA TENT OFFICE.

SAMUEL CHRISTOPHER MCKEOWN, OF NEWARK, NEW JERSEY,

ASSIGNOR TO I SPLIT- DORF ELECTRICAL COMPANY, or NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY.

To all whom it may concern:

Be it known that I, SAMUEL CHRISTOPHER MoKnowN,-a citizen of the United States, residing at N ewark,'in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Starting Mechanism for Magnetos, of which the following is a specification, reference being had to the accompanying drawing.

This invention relates to ignition systems in which a magneto is employed. This magneto is commonly of the high tension type and is positively driven in relation to the engine crankshaft.

. Anobjectof the invention is to provide means interposed between the magneto proper and the driving shaft therefor, whereby the magneto maybe operated by hand while the engine, to which it is connected, is at rest. v

A further object of my invention is to combine the actuating means with the magneto, so that the said means will form a unitary part thereof, and the various parts of the same will be individually supported on the magneto, thereby always maintaining their. proper relative position thereto.

A'further object is to improve the construction and reduce the number of parts necessary to accomplish the result and to arrange these parts so that the danger of;

missing fire and the necessity for frequent adjustment are eliminated.

For the sake of illustration, I will show my invention as applied to an ignition magneto on an aeroplane engine. The invention isparticularly applicable to starting aeroplane engines, and I therefore describe the same in connection therewith, although it will be understood that the invention may be employed in connection with a magneto used for any other purpose in which it is desired to operate the magneto while its driving means are at rest.

Referring to the accompanying drawings, in which like figures of reference denote the same parts whereverthey are shown Figure l is a section through the starting mechanism as mounted on the magneto;

Fig.2 is an end elevation, partly in section, through the starting mechanismyand' .Figs. 3,4, 5, 6, 7' and 8 show the action of the pawl-receding feature whereby the pawl is held out of engagement when the magneto is in normal rotation.

- Specification of Letters Patent.

. STARTING MECHANISM r03. MAeNETos.

Patented Sept. 6, 1921.

Application filed July 11, 1917. Serial No. 179,848.

The numeral 1 denotes what may be termed the magneto member of a coupling, whichserves to connect the magneto and its driving shaft. This coupling is keyed on to the magneto shaft 2 and is secured by a washer 3 and a nut 4. 5 denotes the remainmg half of the coupling, which is secured in rotatable relation to the coupling 1, and carries the inwardly projecting pin 5 positioned between the driving spring 6 and the buffer spring 7. 5 is positively driven from the engine in any suitable manner and when 5 rotates, pin 5, engages the spring 6, which transmits the motion to the fixed post 6 which is a part of the member 1, and there fore the motion of 5 is'transmitted to 1.

The drum 8 is partially rotatable on the frame 9, which fits onto one of the magneto end plates. Interior to this drum and mounted on frame 9 is a spring friction ring 10, frictionally engaging the frame 9 and tending to resist rotation as hereinafter described. Drum 8 is held normally in the position shown at Fig. 2 with the projection 11 against the stop pin 12. This is caused by the tension of spring 13, which is anchored to the screw pin 14 in the drum and 15 in' the frame 9. This spring is tapered in order to offset a tendency of the accumulative friction of each successive convolution of the spring as it winds on the drum to cause undue stretching of that portion of the spring extending from where it leaves the drum to a the post.

The starting cable 16 is wrapped around the drum 9 in an opposite direction to' the spring 13 and being secured to the drum, it will rotate the drum against the tension of said spring when pulled. 17 is a pawl designed to engage a notch in the coupling member 1, and spring 18 gives this pawl an in'wardtrend. p

The description of the remaining parts of the device may best be given in connection with the operation of the same and this is as follows: w V

The engine is'turned'over to draw in a charge and is stopped somewhere between 5 and 36 degrees retarded, care being taken to have the spark advance lever on the magneto in full retard. The aviator then takes influence of spring 18, rides down the slope y on stationary ring 20, coming sooner or later into engagement with a notch in member 1, and compelling same against spring 6 until the pawl rides up on cam surface 2 letting member 1 secured to rotor of magneto, fly back (clockwise) due to re action of spring 6, the buffer spring 7 serving to ease the shock and bring the parts to rest relatively to each other. This generates a current in the magneto in a well understood manner, the spark occurring in the particular cylinder then under compression and connected to the 'distributer of the magneto in the ordinary manner. Simultaneously with the release of the pawl it rides up on slope 00 of ring 20 where it remains until the cable is released and the drum 8 starts on its return stroke. Ordinarily the pawl would now drop back into possible engagement with a notch on 1, which member may be rotating by this time. To guard against this, the aforementioned spring frictionring 10 comes into action, being moved counter clockwise by screw head 19 and clockwise by the back of pawl 17, the latter condition obtaining when the drum 8 starts on its return stroke. The complete cycle of operation of this ring 10 will be better understood by reference to Figs. 5 to 8, inclusive. When the drum 8 which carries the pawl 17 starts rotating in the direction of the arrow at Fig. 5, the friction ring 10 stands still. The recess on the end 7' of the pawl 17 moves away from the end q, to push the pawl 17 down when the inclined portion y of the member 1 is past, (see Fig. 6) the screw 19 in the drum 8, comes against the end p of the ring 10, and drives it also in the direction of the arrow. A little farther on its travel, the cam 2 Fig. 2 pushes the pawl up, releasing the impulse mechanism, and the pawl lands on the incline m Fig. 7, at the end of the drums movement in that direction. On starting to return to normal, as shown in Fig. 8, the drum 8 and pawl 17 move in the direction shown by the arrow, and the ring);

remains still until engaged by the end 1' of the pawl 17. The end of the ring holds the pawl out of engagement while it is returning to normal, the ring being driven by the pawl against the end g of the ring. The normal position of the ring and pawl is-shown at Fig. 5.

Having thus described my invention, what I claim as new and desire to secure'by Letters Patent, is

1. An ignition apparatus including a magneto having a flux shifting member, means for rotating said flux shifting member including a spring for pressing said flux shifting member in the direction of its normal rotation, a manually operated member movable in a path concentric to the axis of rotation of said flux shifting member, devices acting automatically for connecting said manually shittable member with the flux shifting member for turning said flux shifting member in a direction opposed to the spring, means for automatically releasing said flux shifting member from said devices to permit the flux shifting member to be operated by \he spring for producing a current for starting ignition, and means for preventing said devices from making connection with the flux shifting member until again manually operated .for moving the flux shifting member.

2. An ignition apparatus including a magneto having a flux shifting member, means for rotating said flux shitting member including a spring forpressing said flux shifting member in the direction of its normal rotation, a drum concentric with the axis of rotation of the flux shifting member, means carried by the drum for engaging the flux. shifting member for moving the same in a direction opposed to the spring, devices for automatically releasing said drum from the flux shifting member during the continued movement or the drum, and means for maintaining said drum disconnected from the flux shifting member until said drum is again moved forward manually for engaging and moving the flux shifting member for another starting operation.

3. An ignition apparatus including a magneto having a flux shifting member, means for rotating said flux shifting member including a spring for normally pressing said flux shifting member in the direction of its rotation, a drum concentric with the axis of rotation of the flux shifting member, means carried by said drum for engaging the flux shifting member for moving the same in a direction opposite to its normal direction of rotation and against; the action of the spring, devices for automatically releasing said means while the drum continues its movement whereby said flux shifting member through the action of the spring is caused to generate a current for starting ignition, and a spring for returning the drum to normal position, a stop for limiting the movement of the drum under the action of the spring and a stop for limiting the movement of the drum-under the action of the operator. 1

4. An ignition apparatus including a magneto havinga flux shifting member, means for rotating said flux shifting member including a spring normally pressing said flux shifting member in the direction of its rotation, a drum mounted on the end plate of the magneto and adapted to be moved about the axis of the rotation of the shiftable member, a pawl carried by said drum, a spring for normally forcing the pawl into engagement with a notch in the flux shifting member, a shiftable device for holding the pawl out of engagement with said notchwhen said drum is in normal position, said devicepermitting the pawl to engage the notch when the drum is'shifted in a directionopposed to'the direction of rotation of the shiftable member and means for releasing the pawl from the shiftable member while the drum continues its movement, said shiftable device operating to hold the pawl out of engagement with the notch while the drum is returned to its normal position. i

5. An ignition apparatus including a magneto having a flux shifting member, means,

for rotating said flux shifting member including a spring normally pressing said flux shifting member in the direction of its rotation, a drum mounted on the end plate of the magneto and adapted to be moved about the axis of the rotation of theshiftable member, .a pawl'carried by said drum, a sprin for normally forcing the pawl into engagement with a notch in the flux shifting member, a shifting device for holding the pawl out of engagement with said notch when said drum is in normal position, said device permitting the pawl to engage'the notch when the drum is shifted in a direc- 'tion opposed to the direction of rotation of the shiftable member and means for releasing the pawl from the shiftable member while the drum continues itsmovement, said shiftable device operating to hold the pawl out of engagement with the notch while the drum is returned to its normal position, a

spring for returning the drum to normal position, a stop for limiting the movement of the drum under the" action of the spring.

6. An ignition apparatus including a magneto having a flux shifting member, means for rotating said flux shifting mem ber including a spring normally pressing said flux shifting member in the direction of its rotation, a drum mounted on the end plate of the magneto and adapted to be moved about the axis of the rotation of the shiftable member, a pawl carried by said drum, a spring for normally forcing the pawl into engagement with a notch in the flux shifting member, a shiftable device for holding the pawl out of engagement with said notch when said drum is in normal position, said device permitting the pawl to engage the notch when the drum is shifted in a direction opposed to the direction of rotation of the shiftable member and means movement of the drum after the pawl has been released from the shiftable member.

7. An ignition apparatus including a magneto having an end plate, a flux shifting member, means for actuating said magneto includingja coupling, a spring interposed between the coupling and the flux shifting member, said spring normally tendingto press the flux shifting member in the direction of its rotation, a buffer spring for limiting the move ment of the flux shifting member relative to the coupling, a drum mounted on the end plate and capable of movement about the axis of rotationof the flux shifting member, a pawl carried by the drum, a spring'normally pressing the pawl into engagement with the flux shifting member, a ring carried by the drum and movable independently thereof, said ring having frictional engagement with the end plate of the magneto whereby it is caused to lag behind the movements of the drum, said ring operating to hold the pawl out of engagement with said flux shifting member when the drum is at a normal position of rest and permitting the pawl to engage the flux shifting member on a movement of the drum in a means for releasing the pawl from the flux.

shifting member during the continuous movement of the drum, means carried by the drum for shifting the ring to engage and hold the pawl released while the drum returns to its normal position of rest.

8. An ignition apparatus including a magneto having an end plate, a flux shifting member, means for actuating said magneto including a coupling, a spring interposed between the coupling and thefiux shifting member, said spring normally tending'to press the flux shifting member in the direction of its rotation, a buffer spring for limiting the movement of the flux shifting member relative to the coupling, a drum movement about the axis of rotation of the flux shifting member, a pawl carried by the drum,- a spring normally pressing the pawl into engagement with the flux shifting member, a ring carried by the drum and movable independently thereof, said ring having frictional engagement with the end plate of the magneto whereby it is caused to lag behind the movements of the drum, said ring operating to hold the pawl out of engagement with said flux shifting member when the drum is at a normal position of rest and permitting thepawl to engage the flux shifting member on a movement of the drum in a direction opposed to the normal direction of rotation of the flux shifting member, means for releasing the pawl from the flux shifting member during the continuous movement of the drum, means carried 0 by the drum for shifting the ring to engage and hold the pawl released While the drum returns to its normal position of rest, a spring for moving the drum to its normal position of rest when released by the operator, a stop for limiting the movement of the drum under the action of the spring and a stop for limiting the movement of the drum by the operator.

9. An ignition apparatus including a magneto having a flux shifting member, means for rotating said flux shifting 1116111? ber continuously to produce ignition current, said means including devices yieldinglypressing said flux shifting member in the direction of its rotation and manually operated means for moving the flux shifting member in a direction opposed to its direction of rotation and automatically releasing the same for producing a current for starting ignition, said manually operated means including a drum and a spring partially en circling said drum for returning the same to its normal idle position, said spring being coiled and of increasing diameter at the portion thereof Which encircles the drum.

In testimony whereof I hereunto aflix my signature in the presence of two witnesses.

' SAMUEL CHRISTOPHER McKEOWN. Witnesses:

DANIEL R. WALLS, M. W. BARTLETT. 

